Was the forecast right for Boston on Mon Sep 14?
Boston, Massachusetts · daily high temperature in °F · forecasts from each model's archived runs, verified against the BOS observations
14 days out, 4 models put Boston's Mon Sep 14 high anywhere from 72° to 79°; by the final call, the day before, the field had settled to a median of 72°. The day verified at 74° against the BOS observations.
UKMO landed closest, off by 0.3°. ECMWF ran 3° cool.
What every model said, at every lead
Forecast highs for Mon Sep 14 as each model's run approached it, recorded from the last archived model run per day. NBM and The Spread's own blend are omitted because they average the other models.
| Lead | AIFS | AIGFS | ECMWF | GEM | GFS | ICON | UKMO | Range |
|---|---|---|---|---|---|---|---|---|
| 15d · 2026-08-30 | — | 83° | — | — | 72° | — | — | 72–83° |
| 14d · 2026-08-31 | 78° | 79° | 78° | — | 72° | — | — | 72–79° |
| 13d · 2026-09-01 | 69° | 66° | 83° | — | 74° | — | — | 66–83° |
| 12d · 2026-09-02 | 79° | 90° | 72° | — | 82° | — | — | 72–90° |
| 11d · 2026-09-03 | 77° | 79° | 85° | — | 75° | — | — | 75–85° |
| 10d · 2026-09-04 | 67° | 68° | 69° | — | 84° | — | — | 67–84° |
| 9d · 2026-09-05 | 84° | 77° | 82° | 64° | 84° | — | — | 64–84° |
| 8d · 2026-09-06 | 72° | 66° | 80° | 69° | 87° | — | — | 66–87° |
| 7d · 2026-09-07 | 72° | 69° | 77° | 70° | 70° | — | — | 69–77° |
| 6d · 2026-09-08 | 73° | 72° | 80° | 73° | 81° | 72° | 77° | 72–81° |
| 5d · 2026-09-09 | 71° | 73° | 78° | 68° | 75° | 75° | 78° | 68–78° |
| 4d · 2026-09-10 | 72° | 72° | 76° | 67° | 73° | 74° | 73° | 67–76° |
| 3d · 2026-09-11 | 72° | 73° | 74° | 71° | 71° | 71° | 75° | 71–75° |
| 2d · 2026-09-12 | 73° | 74° | 73° | 70° | 72° | 72° | 74° | 70–74° |
| 1d · 2026-09-13 | 72° | 73° | 71° | 73° | 72° | 72° | 74° | 71–74° |
| actual | 74° |
What one day can show
A score for one day isn't very meaningful; a useful ranking needs many days of data. See which model has been most accurate in Boston, or in every city The Spread scores.
Forecasts are what each model's archived runs said at the time they were recorded by The Spread; nothing is reconstructed after the fact. Truth is the BOS observations. The actual values are the ones in hand when this day was verified, usually 2 days after the date; a correction published after that is not carried into it. Archive depth varies by city; verified days exist only for dates the archive watched arrive.